Friday, December 23, 2011

so we took lucky star bus out, ...
went to seatlle, had dinner with cathy's family (well, her mom and younger brother) and jason, her friend from high school -- no pics because i hadn't turned asian mode deflect all embarrassment on yet, but expect some from cathy

... so we stayed a night in seattle, which was very foggy and very green and cold but not terribly so

the next day we got up and had delicious scallion pancakes courtesy of cathy's mom and then we set out for the airport to try again

well, there were 100+ seats yet still until ten minutes before the flight should be taking off, they'd let no standby on due to the problems getting an accurate weight estimate (were they turning it into a cargo plane? or just fail on some software package?)... some people had been there 3 or 4 days, which alarmed my friends >__> anyway they cleared all 40 or so standby in the end, including us, and delayed the flight just to get us all on. yay.

13 hours later we arrived in japan. ignore the datestamps, they're all screwed up.

then we used the toilets in Japan. i was amused because i'd been reading about the japanese toilet revolution courtesy of the big necessity, a book i picked up @ mit loading dock sale this term and really like (still working my way through). we also awarded kudos to the sink design.

Thursday, December 22, 2011

well speed update
made cardboard proto of vending machine, final project of mas.863

then CAD'd and emergency lasercut one, but still didn't have time to do electronics :/ (buttons are just stuck on there, and i didn't leave space to route servo wires, and i'm using janky self-made continuous rotation servos / zip tie couplers to springs
but first time really CADing the full thing before creating it! compare hexa-not-quite-dancingpod, which was cut by hand and then CAD'd

anyway, open house happened, then I emergency packed and we took T Red line > south station > lucky star bus to NYC (11:30 pm) ... arrive around 4 am and take J nyc metro to JFK airport.

derp! didn't get on flight seattle > narita, (yay standby) due to some weight balancing fail. (flight left with 34 empty seats)

which works, but uses an arduino and two victor speed controllers -- total overkill. also, terrible UI: it uses a hard to reach switch for fwd/bwd and foot pedals, which little kids have issues reaching even with the awesome!adjustable-car-seat.

speed routing and my inexperience led to use of 24 zero ohm resistors and I still used a jumper :)

hai zero ohm resistor friends

If you look closely, you can see some of the trace fails (compare IRL to board layout) which were probably due to too high error allowances when the fab module was creating the roland modela machine code. See: pins 8 and 9 on the top right side of the topmost IC, the attiny44. They're connected on the board but not on the schematic. I used eagle's erc/drc and it didn't point out a warning so I'm going to assume it was mill code generation settings, not limits of mill capability.

I discovered how useful eagle layers are, even in the interface is terribly clunky.

I create zero-ohm resistors a dumb way that actually turns out to be helpful when populating a lot of them. Since they each have an air wire, I can set air wires to a nice contrasting color and see where they all are:

Another note, I milled out the moles CNC-ly too using GIMP to get the traces I needed, but :/ milled them out too small and had difficulty getting the 3.5mm spacing power connectors to go through the board -- had to carefully use a vise.

when i saw this in stata a few days ago i legitimately wondered for a few seconds which way this was color-coded until I saw a note (cropped out in this pic), which made me smile. At MIT and hopefully in the general world the imperfect gender ratios are really not so noticeable unless you're looking for it. MIT is wonderful (I say this now because I have no finals this term, all project classes that I loved even if I didn't do as well as I'd've liked)

Anyway, there were no citations! so I decided to go off and investigate on my own and treat it as a data visualization exercise (hi, upcoming IAP / startlabs / c2c / metrify).

EDIT: Derp! I data-failed. You can see civil/environmental engineering (course 1 -- see http://web.mit.edu/catalog/subjects.html if you're confused by the numbers) is definitely off. : / messed up copying and pasting somewhere. Will redo this for realz one day (they have data for multiple years, I want to clean it up automatically).

Tuesday, December 13, 2011

to getpersistent keyboard shortcuts / hotkeys in eagle,
since eagle's UI leaves something to desired for me
you need to add lines to the eagle.scr file in the "scr" folder of your eagle installation
e.g. for my windows desktop that is: "C:\Program Files (x86)\EAGLE-5.11.0\scr\eagle.scr"
here's what mine's set at:

# Configuration Script
#
# This file can be used to configure the editor windows.

emergency high-power h bridge
is in progress and due in oh 18 hours or so (still need to finish schematicking). because i'm actually rich (i live off of instant noodles because i'm a cheap student and would much rather spend the money on delicious components for projects), or at least i feel rich when immersed in the general uh resourceful atmosphere of MITERS / east campus, i bought delicious power components. (as opposed to relying on 6.131 lab ones).

anyway so I emergency learned myself some theory. as usual with my schoolwork, the path of this project went "i'm really lost, but too proud to ask for help so let me confuse myself on the internet". several days later, i feel distinctly antisocial and hopeless and take lots of naps. a few days before the deadline, i start trying to do something and gradually i go "whoa it's starting to make sense." then i go "whoa maybe there is hope after all! I should try to complete this in time" followed by "AAAHHH this is due in [too little time] emergency project!!1!1!!"

current WIP progress (clearly not finished and there are errors, need more buscap, mislabeled components, etc) --

Monday, December 5, 2011

round bottle did better than I expected, I guesstimated size with ruler and tried to get it roughly straight with respect to the bed. no "lathe"-like turning tool, but I etched a fairly small area -- approximately straight then, good enough for laser to focus on.

lasercutter: etching glass -- went very quickly. I suspect the anodized aluminum setting may be overkill and can go much faster (perhaps they're settings for straight up etching metal?).

What was this?
last minute crvftmas (everything you give must be "crufted" aka freely obtained, our hall's version of secret santa) gift: laseretch lab glass bottles (clean autoclaved) I got off of reuse a while back

I meant it when I said 50 lbs of lab glassware. 4 boxes. I only took about half from the reuse post too...

pre-etch

Had issues due to irregular shape of bottle with placement and getting it straight :/ oh well (you can't really tell from the photos)

I ended up doing putzputz, winning MASLAB robot, (this year's hall tshirt design, MASLAB team composed of 4 putzen including dfourie), on the back

Also, thicker bottle could not use due to limit of how deep z wise the bed can move o.o

“Many years ago I used to make springs this way on a lathe. We used commercially available untempered spring wire and after we finished we heated up the spring to red hot and dropped it into fish oil to temper it.Some times we would make special custom springs by soft annealing standard off the shelf springs and straightening them to salvage the wire. Then we would rewind them to suit the job at hand and re-temper.”

Material acquisition trip to TAGS (right off of porter square T stop in cambridge, MA, next to shaws and radioshack)

hi, receipt for techfair grant. also if you click for larger pic you can see what I bought

everything I could find at MITERS and that I bought, includes some thin spring steel.
Also, ~2'' OD pvc pipe I wanted to wrap my spring around

First, safety equipment check:

Well, find out pvc pipe does not fit inside chuck (compare to hole) and is just too small to be gripped by OD jaws.

Definitely too big for drill. I'd considered making an adaptor -- smaller pipe that fits in drill with two keys slotted through it, or turned plastic that more closely fits pipe and then has a "handle" that the drill grips -- similar to larger sized drill bits. but then weekend passed and emergency!lab dictated I do simpler thing.

Learned about "flipping" jaws, or in this lathe's case swapping out OD jaws for ID gripping jaws. Thanks shane colton and matthew hon

step one, take jaws out by backing it out all the way with chuck key

they're numbered 1-3 (or 4) and must be engaged by scroll (spiral thing that turns when you turn the chuck key) in that order to have an even grip

Well I can't find the right sized ones,

they're curved. top one's threads are "inner diameter" gripping, but too small for the chuck currently on the lathe

so I gave up and used the smaller diameter aluminum rod stock seen above.

starting it was difficult. There was a preexisting throughhole in the (hollow) rod that I stuck the end of the rod through

So, then I twisted it upward and pressed it to the rod with the glove. This was awkward to do. I immediately applied the square steel stock but you can see I had issues getting it pressed against the stock and creating a uniform spacing, since I only had one hand (spinning the lathe with the other). Surprisingly easy and fast.

yea, very uneven result, will need to do more trials (there went $5 of weldable steel rod, ⅛’’). went very quickly, even by hand.

you can see starting out I didn't get it to follow the rod closely like in the vid, though I am using thicker diam rod